1. Field of the Invention
The present invention relates to a flat panel display and a method of manufacturing the flat panel display. More particularly, the present invention relates to a flat panel display that is effective in high contrast ratio characteristics.
2. Description of the Related Art
A liquid crystal display (LCD) realizes various images by virtue of the optical and dielectric anisotropy of the liquid crystal material. In LCDs, the quality of images depends on directions where it is viewed from.
To overcome the problem that image quality of LCD depends on the viewing direction, a vertically aligned (VA) LCD is strongly recommended these days.
In a VA LCD, liquid crystal molecules, which are between an upper substrate and a lower substrate, are aligned vertically against the surface of the substrates when electric field is not applied. When electric field is applied between the two substrates, the molecules of the liquid crystal (LC) rotate to the direction parallel with the surface of the two substrates.
To reduce the direction dependency of the images and to improve the quality of the image in VA LCD, a multi-domain technology is used. The multi-domain technology is to control the direction of molecules of the LC independently from one domain to another. Openings in electrodes or protrusions on electrodes are used to form multi-domains in VA LCDs. Some LCDs use one of the protrusions and the openings. Some LCDs use both of them.
The protrusions used to form multi-domains are made in the following process.
First, a photosensitive material is coated on a substrate. The photosensitive layer is exposed to an appropriate light through a mask that has a certain pattern.
The photosensitive layer is developed to form the above pattern.
The pattern of photosensitive layer becomes protrusions that form multi-domains.
In this case, the LC molecules on the protrusion is not aligned vertically but inclined to one side.
VA LCD is usually normally black mode which shows black state when electric field is not applied. In order to achieve a normally black mode, the LC molecule should align vertically when electric field is not applied. If some of the LC molecules are not aligned vertically, light will leak in the black state. This degrades the display quality.